Paint strainer



Patented Feb. 2, 17954 v if PAINT STRAINER VMai: Weidner, Racine, Wis., assigner to S. C. Johnson & Son, Inc., Racine, Wis.

Application January 16, '1948, Serial No. 2,599

1 Claim. 1

This invention relates to improvements in strainers. More particularly, theinvention relates to an improved method for straining paint and to novel apparatus for carrying out this method.

In the manufacture of paint after the pigments and vehicles have been mixed and tinted and properly thinned, the paint is usually transferred from, for example, a 1000 gallon storage tank to a smaller vessel for straining and filling into containers.` VInv the past such straining has entailed various methods and apparatus. The product may be passed through screens or riddles of a variety of forms and designs. In other cases loose fibrous material is placed over the screen or riddle, or the screen is vibrated to aid the movement of the liquid through the filtering material. In still other cases paint or enamel is passed through a centrifuge to strain out coarse material.

While all these methods are well known in the art for carrying out the straining operation, they are subject to the disadvantages of limited production due to the length of time necessary to accomplish the straining operation. Many such methods also entail considerable cost in manufacture and installation.

I have thus" provided an improved method for straining paint which comprises passing a charge of unstrained paint through a straining area into a receptacle to a predetermined level, the level being above the point at which the strained paint enters the receptacle, and then introducing additional paint into the straining vessel'. The strained paint is then removed from said receptacle at a rate so that the level of paint remaining in the receptacle is maintained above the point at which the strained paint enters the receptacle. AIt is therefore a primary object of my invention to provide an improved method and apparatus for straining paint which will operate efiiciently, requiring a minimum of time to accomplish the intended result and can be operated with a minimum of expense and labor.

Another object of my invention is to provide an improved method and apparatus for straining paint which can be manufactured and installed economically.

Other objects and advantages of the invention will be more apparent from the following description taken with the accompanying drawing in which:

Figure 1 is a front elevational view of the paint strainer mainly in section.

Figure 2 is a side elevational View of the strainins vessel.

. Figure 3 is a top plan View of the straining vessel.

Similar numerals refer to similar parts throughout the several views.

The paint strainer, generally designatedI `by the numeral I0, includes a straining vessel II having a greater circumference at its top than at its bottom. At the top of the straining vessel I I is aixed a cheesecloth screen or other similar porous filter element It.V rThe bottom area ofv the Vessel II consists essentially of a foraminous plate or wire screen I3. The straining vessel II is securely but detachably positioned Within an open receptacle III and is held or rendered impervious to air by means of a gasket I5. An air release vent I 6 is positioned on the receptacle I4 somewhere intermediate the top and the wire screen I3. Preferably, however, it is positioned near the top of receptacle I4 as shown in Figure 1.

At the lowest point of the funnel-bottomed receptacle I4 a paint discharge outlet Il is positioned, and attached thereto is a molasses gate valve I8 for controlled withdrawal of the paint from the receptacle Ill. It will be readily'understood that the dischargel outlet I'I, if desired, may be positioned on the side of receptacle IfI if preferred. Y

In operation, unstrained paint is iiltered through the filter cloth I2 and wire screen I3, thereby eliminating undesirable material, such as skins and dirt, until the paint arrives at a level above the wire screen I3. The air release vent I6 is then opened allowing air entrapped in the area between the top of the receptacle Id and the paint level to escape. disengagement of the molasses gate valve IB and withdrawal of the strained paint, a vacuum is created which quickens the egress of the paint from the receptacle IIS. The process can be made continuous by regulating the amount of paint being continuously introduced to the lter I2 and vthe amount of strained paint vbeingA withdrawn.

The effectiveness of the operation can best be illustrated by the following examples:

Example I A 1000 gallon storage tank is filled with unstrained paint. A charge of .unstrained paint from the storage tank was filtered through the paint-straining apparatus hereinbefore described and shown in the drawing, except that the straining vessel Il was not attached to the receptacle I4 by means of a gasket I5 in order to` render the junction of the vessel II and receptacle I4 airtight. As soon as a charge of paint Therefore, upon 3 was flowed upon the filter cloth I2 the molasses gate valve I8 was opened and the strained paint owed into a 55 gallon drum. The rate of ilow of the unstrained paint upon lter cloth I2 was at the maximum rate that the lter cloth could handle. The molasses gate valve I6 was open to its maximum capacity andthe rate ,of vlow from the receptacle I4 into the duim wasfsuch that it took about 25 minutes to ll the drum to capacity.

Example I I The above example was repeated except that the paint strainer used was Athat describedzin detail in the specification and shown in the accompanying drawing. A charge of unstrained paint was flowed upon the nlter cloth I2 and the air vent I6 and molasses gate valve I8 remained closed until the level of strained paint in the receptacle I4 Was above :the Wire screen I3. vThe air vent I5 was then opened to discharge the entrapped air presentin .the receptacle I4. After the entrapped air Was ventedgthe air vent .I5 was closed. The molasses gate valve I8 was. vthen opened and the charge of unstrained paint owed upon the filter I2 was continued at a rateconstant with the amountvofy strained paint'being- Withdrawn through the molasses gate valve I8. The rate of withdrawal of the lstrai-r-ied paint by the effect of the Vacuum hereby created was suchvthat a' 55 gallon drum was lil-led in 2% yminutes `or in the time needed in Example 1.

To illustrate that this-invention does not reside solely in the positioning of the strainer II into the receptacle I4- -insuchzman-ner as torender itim-pervious .to air the following exam-ple was carried out:

' Example -III Example 2 was repeated except thatthe level of the strained paint in the receptacle I4 was intentionally maintained at a point lower than its point of introduction of .paint into the receptacle I4 through the wire screen I3. It was found that the rate of owrthrough the molasses gate I3 was not substantially greater than the rate `of now in Example 1.

It will be readily understood that Examples l, 2 and 3 were used for purpose of illustration only. The rate of now of strained. paint through the apparatus of this invention bythe method hereinbefore described will depend somewhat Aupon' the .consistency of the paint to `be `strained andthe sizeof the strainer. However, lby the use of my method, I have found that paint can be strained in ,1/5 to 'the timeprevious'lyneeded for such straining.

While I have shown thepre-ferredapparatus for carrying out my .method it will :be understood that other apparatusesmay be used,l providing that the point of introduction of thepaint into the receptacle shallbe below 'the levelof the paint maintained in the receptacle and further providing that the strainer be positioned in the receptacle impervious to air with proper air vents being provided in the receptacle.

Thus, in accordance with my invention, I have provided an efficient paint strainer Which may be manufactured and employed at a minimum of expense, .nevertheless accomplishing an reilicient straining operation in minimum time.

What is claimed is:

An improved method for straining paint, comprising. passing a charge of unstrained paint through a straining vessel into a receptacle, having an air-tight juncture with saidY vessel, to a level Within said receptacle above the point at Which. said paint enters the receptacle through said vessel, releasing the air entrapped above the strained paint between the inner periphery of said receptacle and the outer periphery of `said straining vessel, immediately thereafter closing the means for said release of air and-discharging they strained paint from said receptacle Whileintroducing additional unstrained paint into v,said receptacle through said vessel at a rate sumcient to maintain the paint level in said receptacle above the level at which said paint entered said receptacle through said straining vessel.

MAX EI'DNER.

References Cited in the le of this patent UNITED STATES PATENTS Y Number Name Date 65,515 Spencer June .41, .1867 94,298 .Espent Aug.1.31,. y18.69 374,875 vLyman Dec. `13,.:1887 453,798 Gersdorii" June.9,. 1891 473,081 Rahn --..Apr.. 19; v1892 626,9Ql Eberhard June 13', 1899 1,020,986 Jozsef ;Mar.- 26, 1912 1,115,505 yChapin iNov. 3, 1914 1,429,488 Capro Sept.. .19, .1922 2,251,684 Lomax Aug. 5; 5194.1 2,449,238 Lightfoot, Jr Sept. 14, `lies 2,450,510 Hanson `(25ct..- 5, 1948 FOREIGN PATENTS Number Country v, Date 1,367 Great Britain -..11,892 y'21,120 GreatBritain 1-, .1904 4,929 France Sept 11,190.5

First .addition .130.353 ,4:15

. .509,931 Germany Oct.v 1,14., 19.30

OTHER REFERENCES Filtration and Filters, vby Pickard published 1929 by Ernest `Benan, Ltd., London, Bou-verlo House, E. C. 4. Page 37 cited.

Fischer Scientic Co., .Modern Laboratory Appliances, page 625 cited, copyright 1934 by `Ifis-he-r Scientific Co., 7091*"orbes` St., Pi-ttsbnrghpa. 

